This invention relates generally to a cleaning method, and more particularly, concerns a method for sequenced retraction of the cleaner from the photoreceptor surface.
In the image on image, multi-pass color development process, four layers of color toner (black, cyan, yellow and magenta) are developed onto the photoreceptor before transfer to paper. A separate cycle of the photoreceptor is required to accomplish the development of each color toner layer. To avoid disturbance of these images as the color toner layers are being developed, the cleaning elements must be disengaged from the photoreceptor surface until after the four toner layers have been developed and transferred to paper. After the toner image has been transferred to the paper the cleaning elements must be re-engaged to the photoreceptor to clean any residual toner which failed during transfer. In order to maintain a high productivity level, the cleaning elements should disengage and engage the photoreceptor within the space of the interdocument zones. This requires that the disengagement and engagement occur over fairly short time periods which will depend on the length of the interdocument zone and on the photoreceptor process speed.
Several copiers presently use the multi-pass process before a single transfer step. The Konica 9028 machine uses a blade cleaner which is retracted from the photoreceptor drum while the color images are being developed. The Panasonic FP-C1 machine uses a single electrostatic brush cleaner which is retracted by a cam from the drum photoreceptor. The Sharp CX7500 machine uses an intermediate belt and a dual blade cleaner which is retracted from the photoreceptor belt by a solenoid during color image development. The primary, high load, blade is also retracted when the photoreceptor seam passes under the blade to avoid a motion quality disturbance.
The following disclosure may be relevant to various aspects of the present invention and may be briefly summarized as follows:
U.S. Pat. No. 4,669,864 to Shoji et al. discloses an image forming apparatus having a cleaning device arranged on the outer periphery of an image retainer, and bringing the device into and out of abutment against the image retainer, wherein the cleaning device comprises a first cleaning member and a second cleaning member arranged downstream of the first cleaning member in the moving direction of the surface of the image retainer. A cleaning operation of the second cleaning member against the image retainer is conducted according to a time at which the cleaning operation of the first cleaning member against the image retainer is conducted.